A streamlined acquisition for mapping baseline brain oxygenation using quantitative BOLD.

Area of Science:

• Neuroimaging
• Biophysics
• Medical Physics

Background:

• Quantitative BOLD (qBOLD) offers non-invasive brain haemodynamic and metabolic measurements.
• Existing qBOLD methods can be affected by confounding signals, limiting clinical feasibility.
• Accurate mapping of baseline brain oxygenation is crucial for understanding neurological conditions.

Purpose of the Study:

• To refine the qBOLD methodology for clinical feasibility in mapping baseline brain oxygenation.
• To introduce streamlined-qBOLD, incorporating specific techniques to minimize signal contamination.
• To improve the robustness and accuracy of quantitative brain oxygenation parameter maps.

Main Methods:

• Developed streamlined-qBOLD using Fluid Attenuated Inversion Recovery (FLAIR) for CSF suppression, Gradient Echo Slice Excitation Profile Imaging (GESEPI) for magnetic field gradient reduction, and Asymmetric Spin Echo (ASE) for R₂' measurement.
• Employed a theoretical optimization framework to enhance signal-to-noise ratio.
• Acquired data from a healthy subject group (n=7).

Main Results:

• CSF nulling effectively reduced apparent R₂' elevations caused by partial volumes.
• CSF suppression led to significant decreases in R₂' (p < 0.001) and deoxygenated blood volume (p < 0.01) in cortical grey matter.
• Streamlined-qBOLD produced quantitative baseline brain oxygenation parameter maps comparable to literature values.

Conclusions:

• Streamlined-qBOLD provides a clinically feasible and robust method for mapping baseline brain oxygenation.
• The implemented techniques effectively minimize confounding signals, improving quantitative accuracy.
• This refined qBOLD approach holds promise for enhanced neuroimaging applications.